Nastassya Filippovna tells the maid to invite Rogozhin and his company into the drawing room. The guests look at one another in amazement. General Yepanchin tries to leave, but Nastassya Filippovna persuades him to stay. The general and Totsky briefly exchange the opinion that she may be going insane. Two additions to Rogozhin's rowdy company of lowlifes include a boxer, an ex-editor of a newspaper, and a sub-lieutenant whom the others call a beggar. Rogozhin, overcome with veneration for Nastassya Filippovna from the moment he enters her apartment, places a thick package on the table, saying it contains 100,000 rubles.
Nastassya Filippovna begins a long, emotionally intense speech. She notes her disbelief at the fact that Ganya could possibly want her after she has accepted the general's pearls and has been the object of Rogozhin's bargaining. She says she was foolish to think she could enter an honorable family such as Ganya's. He was willing to let her do so only because he would do virtually anything for money. Nastassya Filippovna then turns to Totsky and tells him that she has been living in anger and spite for him. She describes how he visited her when she was a young girl, slept with her, and then left. She says she could have married him but decided he was not worth her anger. She decided she would rather live on the streets, a more proper place for a woman such as herself. She exclaims that no one would take her now.
Ferdyshchenko says Prince Myshkin would take her, and the latter agrees. The prince stands up and proposes to her, calling her an honest woman and saying she does not deserve all the blame she has received. He then announces that he has money to support her because he just received news of a large inheritance. The guests are amazed.
After Ptitsyn corroborates the legitimacy of the letter, everyone is so shocked by the news that they practically forget about Nastassya Filippovna, which drives her in utter delirium. She agrees to marry Myshkin, who assures her that she should not blame herself for what happened between her and Totsky. However, she exclaims that the prince deserves to marry a respectable woman, someone like Aglaya Yepanchin, and that she, Nastassya Filippovna, will leave with Rogozhin. Though she has always dreamt of someone like Myshkin, she says she does not belong with him.
Before Nastassya Filippovna leaves, she decides to pay Ganya back for all the suffering he has caused her. She throws the package of 100,000 rubles into the fireplace; once it has caught fire, she says that only Ganya can go and get it if he is willing. Ganya faints. Nastassya Filippovna retrieves the money, saying that Ganya's vanity is clearly stronger than his avarice. Ganya then announces that the package is his, and he leaves. The prince runs off after them.
Totsky and Ptitsyn briefly discuss what has happened. Ptitsyn compares Nastassya Filippovna's actions to an old Japanese custom in which the offended punishes his offender by committing suicide right in front of his face. Totsky replies that with Nastassya Filippovna's beauty and extraordinary character, it is a shame that all is lost.
The emotional intensity of the party has been rising slowly for the last several chapters; Rogozhin's arrival further escalates the drama, much as it does during the scandalous scene at the Ivolgins. Rogozhin's dirtiness, along with the impropriety of his companions, sharply contrasts with the elegance of Nastassya Filippovna's apartment and the German beauty. Indeed, Rogozhin steps on her beautiful, blue, lace-decorated dress with his dirty boots—an action that symbolizes the invasion of the dirty lower world into high society. Rogozhin's arrival also brings an element of delirium, fever, and insanity, all of which further raise the emotional height of the drama.
These two concluding chapters of Part I do much to reveal the psychology and motivations of Nastassya Filippovna. She believes herself unworthy of entering an honorable family such as the Ivolgins. She also believes she does not deserve to marry someone as respectable, innocent, and good as Myshkin, even though he represents everything she has dreamt of since she was a young woman. Instead, Nastassya Filippovna claims she belongs on the streets. She despises Ganya for his willingness to do anything for money. The predominant feeling she expresses, however, is her spiteful rage toward Totsky. Though he is the reason for all of her miseries, she nevertheless blames herself and feels herself unworthy of truly honorable company.
Perhaps Nastassya Filippovna's desire to run off with Rogozhin is her way of avenging her miseries on Totsky. Rogozhin represents the world of darkness, delirium, and dirtiness; his troupe of lowlifes is surely no company for a refined woman such as Nastassya Filippovna. In addition, Rogozhin has purchased her with 100,000 rubles—essentially an act of high-society prostitution. She decides to run off with him not only because she believes she deserves this kind of fate, but also because ruining herself would be a form of revenge against Totsky. At the end of Part I, Ptitsyn tells Totsky of a Japanese custom: when one feels offended by another, one goes to the offender and kills himself in front of the offender. Symbolically, Nastassya Filippovna commits such an act of hara-kiri in front of Totsky, running away with Rogozhin and therefore consciously ruining her own life. She wants to show Totsky how much misery he has caused her and that he has driven her to self-destruction.
By proposing to Nastassya Filippovna, Myshkin attempts to save her from the world of destruction that Rogozhin represents. Unlike the all-devouring passion of Rogozhin, the prince offers her kindness and love that promises redemption of her sins and rebirth. Myshkin is unable to convince Nastassya Filippovna to stop blaming herself, and she refuses to accept this love. She decides to stick with her plan and leave with Rogozhin instead. Before she does so, however, she subjects Ganya to a psychological test. In order to test the limits of his ambition and thirst for money, she throws the 100,000 rubles into the fireplace. Ultimately, Ganya shows he is more vain than he is greedy.